AUTOANTIBODIES AGAINST EUKARYOTIC PROTEIN L7 IN PATIENTS SUFFERING FROM SYSTEMIC LUPUS-ERYTHEMATOSUS AND PROGRESSIVE SYSTEMIC-SCLEROSIS - FREQUENCY AND CORRELATION WITH CLINICAL, SEROLOGICAL AND GENETIC-PARAMETERS

Recent studies have shown that sera of patients suffering from systemi c autoimmune diseases contain autoantibodies directed against the euka ryotic ribosomal protein L7 [1]. In the present study we screened a la rge panel of sera from patients with systemic lupus erythematosus (SLE ) for the presence of anti-L7 autoantibodies and their relationship to clinical, serological and genetic parameters of SLE. By means of an E LISA employing recombinant protein L7 as antigen we detected anti-L7 a utoantibodies in 172 of 506 SLE sera (34%). Negative correlations were observed between the presence of anti-L7 autoantibodies, serum IgG le vels and proteinuria; a potentially positive relationship existed with lung fibrosis. In order to analyse further this possibility we screen ed sera of 129 patients suffering from progressive systemic sclerosis (PSS) for anti-L7 reactivity; 45 of these patients had lung fibrosis. Of the PSS patients, 41% exhibited anti-L7 autoantibodies, but positiv e reactions were evenly distributed among patients with and without lu ng fibrosis. Protein L7 thus represents a major autoantigen of systemi c autoimmune diseases, but does not so far define a distinct subpopula tion of patients.